High-entropy nitrides from dual entropic and enthalpic forces for high-efficiency oxygen evolution reaction

The development of high-entropy materials as active and durable catalysts for oxygen evolution reaction is important but challenging for hydrogen production from water electrolysis. In contrast to conventional synthesis strategies that usually involve high-temperature annealing, a novel poly(ethylene glycol)-barbituric acid deep eutectic solvent-assisted strategy was developed in this work to successfully synthesize high-entropy nitrides (HENs) (FeCoNiCuZn)N at a record low temperature of 473 K. Multiple analytical characterizations illustrate that dual entropic and enthalpic forces provided by the poly(ethylene glycol)-barbituric acid deep eutectic solvent play a critical role in the low-temperature synthesis of HENs. The prepared HENs have a microsphere structure consisting of five highly dispersed active metal (Fe, Co, Ni, Cu, and Zn) species, which are conducive to boosting oxygen evolution reaction performance in alkaline media, in terms of a low overpotential of 223 mV at 10 mA cm⁻² and sustained durability over 30 hours at 400 mA cm⁻². This work paves the way for the fabrication of high-entropy materials with excellent electrocatalytic properties for future energy conversion and storage applications.